Korean Journal of Chemical Engineering (v.35, #6)
Random forest classifier for real-time chemical leak source tracking using fence-monitoring sensors by Hyunseung Kim; Addis Lulu Gebreselassie; Seungkyu Dan; Dongil Shin (1231-1239).
Fast and reliable diagnosis of chemical leak and leak location(s) can save lives and reduce the damage from chemical accidents by enabling quick response. This paper presents a method that uses random forest (RF) classifier to track the location of chemical leak in real-time. A set of big data of leak accidents, which is needed to learn the RF classifier, is extracted by performing massive CFD simulations on a real chemical plant. The RF model is designed with optimal parameters and descriptors through parameter effect experiment. Feature ranking is also implemented to eliminate unnecessary attributes from the dataset. Using the pre-processed data, the optimal RF model achieved a test accuracy of 86.9% for the classification problem of predicting the leak location among 40-potential leak sources in the plant. Furthermore, when analyzing prediction errors by visualizing the classification boundary of RF model, most of the prediction errors are confirmed to be misclassification of adjacent leak locations. Considering the high prediction accuracy of the RF model, the RF-based leak source tracking model is expected to be effectively applied to industrial leak accidents.
Keywords: Chemical Leak Accident; Source Tracking; Inverse Problem; Random Forest; Artificial Intelligence
Development of batch proportional-integral-derivative controller by Won Hyun Kwon; Kyung Hwan Ryu; Jung-A Hwang; Kyeong Hoon Kim; Jay H. Lee; Su Whan Sung (1240-1246).
Previous batch control methods, such as iterative learning control (ILC) or run-to-run (R2R) control, can significantly improve the control performance of the batch process. However, to guarantee the expected good control performance, a fairly accurate process model is required for these controllers. Also, the implementation is numerically complicated so that it is difficult to be applied to real manufacturing processes. To overcome these problems, a new batch proportional-integral-derivative (PID) control method is proposed, which borrows the concept of the conventional PID control method. Simulation studies confirm that the proposed method shows acceptable performance in tracking a setpoint trajectory, rejecting disturbances, and robustness to noises and variation of process dynamics. The application to the commercial batch process of a single crystal grower verifies that the proposed method can significantly contribute to improving the control performances of real batch processes.
Keywords: Batch Process; Batch Controller; Batch PID Controller; Feed Forward Controller; Czochralski Process
Effect of vertically varying permeability on the onset of convection in a porous medium by Won Sun Ryoo; Min Chan Kim (1247-1256).
Considering the vertically varying permeability of a porous medium, we conducted theoretical and numerical analyses on the onset of buoyancy-driven instability in an initially quiescent, fluid-saturated, horizontal porous layer. Darcy’s law was employed to explain the fluid flow through a porous medium and linear and nonlinear analyses are conducted. In the semi-infinite domain, the growth of disturbance and the onset of convection were analyzed with and without the quasi-steady state approximation. The present analysis of initial growth rate shows that the system is initially unconditionally stable regardless of a vertical heterogeneity parameter. The onset conditions of buoyancy-driven instabilities were investigated as a function of the Darcy-Rayleigh number and the heterogeneity parameter. To find the effect of a vertical heterogeneity on the flow after the onset of convection, nonlinear numerical simulations also were conducted using the result of the linear analysis as a starting point. Nonlinear numerical simulations show that the finger-like instability motion is not readily observable at a critical time and it becomes visible approximately when a mass transfer rate substantially increases.
Keywords: Buoyancy-driven Convection; Onset Condition; Vertically Heterogeneous Porous Medium; Linear Stability Analysis; Direct Numerical Simulation
Effect of solid residence time on CO2 selectivity in a semi-continuous chemical looping combustor by Doyeon Lee; Ho-Jung Ryu; Dowon Shun; Dal-Hee Bae; Jeom-In Baek (1257-1262).
Chemical looping combustion (CLC) is a promising technology for fossil fuel combustion with inherent CO2 capture and sequestration, which is able to mitigate greenhouse gases (GHGs) emission. In this study, to design a 0.5MWth pressurized chemical looping combustor for natural gas and syngas the effects of solid residences time on CO2 selectivity were investigated in a novel semi-continuous CLC reactor using Ni-based oxygen carrier particle. The semi-continuous chemical looping combustor was designed to simulate the fuel reactor of the continuous chemical looping combustor. It consists of an upper hopper, a screw conveyor, a fluidized bed reactor, and a lower hopper. Solid circulation rate (G s ) was controlled by adjusting the rotational speed of the screw conveyor. The measured solid circulation rate increased linearly as the rotational speed of the screw increased and showed almost the same values regardless of temperature and fluidization velocity up to 800°C and 4 U mf , respectively. The solid circulation rate required to achieve 100% CH4 conversion was varied to change G s -fuel ratio (oxygen carrier feeding rate/fuel feeding rate, kg/Nm3). The measured CO2 selectivity was greater than 98% when the Gs-fuel ratio was higher than 78 kg/Nm3.
Keywords: Chemical Looping; Oxygen Carrier; Fuel Conversion; CO2 Selectivity; Solid Residence Time
Kinetic models of Fischer-Tropsch synthesis reaction over granule-type Pt-promoted Co/Al2O3 catalyst by Hyun Mo Koo; Myung June Park; Dong Ju Moon; Jong Wook Bae (1263-1273).
Kinetic models of CO hydrogenation to paraffinic hydrocarbons through Fischer-Tropsch synthesis (FTS) reaction were studied by using Langmuir-Hinshelwood Hougen-Watson (LHHW) model of 16 different reaction steps with a pseudo steady-state assumption (PSSA) on the prototype Pt-promoted Co/Al2O3 catalyst having a granule size of ∼1 mm of spherical γ-Al2O3 support (surface area of 149m2/g). The derived kinetic models from ten sets of experimental data by altering the reaction conditions such as temperatures, pressures, space velocities and H2/CO molar ratios were found to be well fitted with reasonable kinetic parameters and small errors of conversion of CO and hydrocarbon distributions in terms of mean absolute relative residual (MARR) and relative standard deviation error (RSDE). The derived reaction rates and CO activation energy of -86 kJ/mol well correspond to the our previously reported results using power-type catalysts. Based on the LHHW model with PSSA, the possible chemical intermediates on the granule ball-type Co-Pt/Al2O3 surfaces were precisely considered to explain the typical adsorption, initiation, propagation and termination steps of FTS reaction as well as to derive elementary reaction rates with their kinetic parameters and hydrocarbon distributions. The derived kinetic models were further used to verify temperature-profiles in a pilot-scale fixed-bed tubular FTS reactor with a packing depth of 100 cm catalyst, and it confirmed that the temperature gradients were less than 10 °C in a length of reactor by effectively removing the generated heat by an exothermic FTS reaction.
Keywords: Fischer-Tropsch Synthesis (FTS) Reaction; Cobalt-based FTS Catalyst; Kinetic Parameter Estimations; Langmuir-Hinshelwood Hougen-Watson (LHHW) Model; Pseudo Steady-state Assumption (PSSA)
Bioactivity kinetics of organic matter biodegradation and nitrification by Jianhui Wang; Lu Wang; Enyan Cui; Hai Lu (1274-1280).
Biodegradation of organic matter and nitrification of ammonia nitrogen was studied by measuring the electron transport system (ETS) activity in activated sludge. The feasibility of characterizing the bioactivity of activated sludge based on the ETS was discussed. Then, bioactivity kinetics for the biodegradation and nitrification of organic matter was analyzed using the Michaelis–Menten equation. The results indicated that the ETS activity of activated sludge reflects the progression of organic matter biodegradation and nitrification of ammonia nitrogen; moreover, ETS activity is sensitive to the loading of organic matter and ammonia nitrogen and also to changes in alkalinity during the reaction. Therefore, it is feasible to characterize the bioactivity of an activated sludge system with ETS activity. The Michaelis constant for organic matter biodegradation was K T s=368.9 mg/L; U T m=90.9 mgTF/(gTss·h); K I s=88.42 mg/L; and U I m=277.8 mgINTF/(gTss·h); for the nitrification of ammonia nitrogen, the Michaelis constant was K T s=16.89 mg/L; U T m=34.6 mgTF/(gTss·h); K I s=6.0 mg/L; and U I m=196.08 mgINTF/(gTss·h). Additional analyses of bioactivity kinetics confirmed that the organic matter oxidation rate of heterotrophic bacteria was higher than that of autotrophic nitrifying bacteria.
Keywords: Organic Matter Biodegradation; Nitrification; ETS Activity; Activated Sludge; Kinetics
Separation of heavy metal and protein from wastewater by sulfonated polyphenylsulfone ultrafiltration membrane process prepared by glycine betaine enriched coagulation bath by Irfana Kolangare Moideen; Arun Mohan Isloor; Asif Ali Qaiser; Ahmed Fauzi Ismail; Mohd Sohaimi Abdullah (1281-1289).
This work deals with a simple and eco-friendly approach for the development of ultrafiltration membranes for the separation of environmentally hazardous substances from the water source. Polysulfone and sulfonated polyphenylsulfone blend ultrafiltration membranes were fabricated by the non-solvent induced phase inversion technique. Prepared membranes were characterized for their morphology, hydrophilicity, porosity, filtration and antifouling properties. The blend membranes with 15 wt% of sPPSU demonstrated the best performance with water flux of 190.33 Lm−2h−1 and flux recovery ratio of 86.56%. The effect of aq. glycine betaine (GB) coagulation bath on the membrane property and performance was studied and compared with commonly used additives such as NaCl and NMP. The GB in coagulation bath exhibited better flux and performance with protein rejection of 66.3%, 74.0% and 91.2% for trypsin, pepsin, and bovine serum albumin, respectively, and heavy metal rejection of 75.2% and 87.6% for polymer enhanced ultrafiltration of Cd2+ and Pb2+ ions, respectively.
Keywords: Sulfonated Polyphenylsulfone; Glycine Betaine; Coagulation Bath; Protein Rejection; Heavy Metal Rejection
Valorization of chitosan into levulinic acid by hydrothermal catalytic conversion with methanesulfonic acid by Hyo Seon Kim; Mi-Ra Park; Sung-Koo Kim; Gwi-Taek Jeong (1290-1296).
As a potential renewable aquatic resource, chitosan is the second most abundant biopolymer. Methanesulfonic acid is a catalyst that is strongly acidic and biodegradable. We used chitosan and methanesulfonic acid to produce platform chemicals via an acid-catalyzed hydrothermal reaction. In the methanesulfonic acid-catalyzed hydrothermal conversion of chitosan, an optimal levulinic acid yield of 28.21±1.20% was achieved under the following conditions: 2% chitosan and 0.2 M methanesulfonic acid at 200 °C for 30 min. These results indicated that a combination of chitosan and methanesulfonic acid would be suitable for platform chemical production.
Keywords: Chitosan; Methanesulfonic Acid; Platform Chemicals; 5-Hydroxymethylfurfural; Levulinic Acid
His-tagged protein immobilization on cationic ferrite magnetic nanoparticles by Sung Jin Park; SeungYeon Kim; Seung Hoon Kim; Kyung Min Park; Byeong Hee Hwang (1297-1302).
Magnetic nanoparticles have been applied in various fields because of their interesting magnetic properties. Immobilization on magnetic nanoparticles is a very important step in functionalizing them. We examined protein immobilization efficiency using interactions between his-tagged enhanced green fluorescence protein and affordable cationic ferrite magnetic nanoparticles for the first time. Four types of ferrite magnetic nanoparticles were verified: cobalt iron oxide, copper iron oxide, nickel iron oxide, and iron (III) oxide as negative controls. Among the four ferrite magnetic nanoparticles, copper ferrite magnetic nanoparticle was confirmed to have the highest immobilization efficiency at 3.0 mg proteins per gram ferrite magnetic nanoparticle and 78% of total enhanced green fluorescence protein. In addition, the maximum binding efficiency was determined for copper ferrite magnetic nanoparticle. Consequently, this newly verified his-tag-immobilizing capacity of copper ferrite magnetic nanoparticle could provide a facile, capable, and promising strategy for immobilizing his-tagged proteins or peptides with high purity for biosensors, magnetic separation, or diagnostics.
Keywords: Protein Immobilization; Magnetic Nanoparticles; Iron Oxides; Detection; Diagnosis
Adsorption of Congo Red dye by native amine and carboxyl modified biomass of Funalia trogii: Isotherms, kinetics and thermodynamics mechanisms by Gulay Bayramoglu; Mehmet Yakup Arica (1303-1311).
Native, iminodiacetic acid and triethylenetetraamine modified biomasses of Funalia trogii were used for removal of Congo Red dye (CRD) from aqueous medium. The native and modified fungal biomasses were characterized using ATR-FTIR, Zeta potential, contact angle studies and analytical methods. FTIR studies of the native and chemically modified adsorbent preparations show that amine, carboxyl and hydroxyl groups are involved in the adsorption of the model dye (i.e., Congo Red). The maximum adsorption of the CRD on the native, carboxyl and amine groups modified fungal biomasses was obtained at pH 5.0. The amount of adsorbed dye on the adsorbent samples increased as the initial concentration of CRD in the solution increased to 200mg/L. The adsorption capacities of native, carboxyl groups and amine modified fungal preparations were 90.4, 153.6 and 193.7mg/g dry adsorbents, respectively. The data was fitted well with the Langmuir isotherm model, and followed the pseudo-second-order equations. Thermodynamic parameters (ΔG o , ΔH o and ΔS o ) were also calculated. The results showed that triethylenetetraamine (TETA) modified biomass of F. trogii presented an excellent dye removal performance and can be used in various environmental applications such as various micro-pollutants removal from aqueous medium.
Keywords: Fungal Biomass; Modification; Adsorption; Congo Red Dye; Surface Complexation; Wastewater Treatment
Efficient conversion of fructose to 5-[(formyloxy)methyl]furfural by reactive extraction and in-situ esterification by Caixia Xiong; Yong Sun; Juan Du; Wei Chen; Zhihao Si; He Gao; Xing Tang; Xianhai Zeng (1312-1318).
5-[(Formyloxy)methyl]furfural (FMF), an analogue of 5-(hydroxymethyl)furfural (HMF) is becoming more attractive due to its superior stability and hydrophobicity, which make it easier to refineand store. In the present study, FMF was produced from fructose by one-pot approach in pure formic acid media or by a two-step approach via HMF in choline chloride (ChCl)/fructose deep eutectic solvents (DES) system. A favorable FMF yield of 63.22% was reached by two-step approach. In addition, the effects of reaction parameters, such as temperature and acidity, on preparation of FMF from fructose were systematically investigated. The dehydration of fructose into HMF was confirmed as the rate-controlling step in the consecutive reaction. Ultimately, the separation and purification procedures of FMF were put forward. The FMF with a purity of 98.8% was obtained finally. Meanwhile, the FMF purified by saturated sodium bicarbonate solution showed an excelled storage stability.
Keywords: 5-[(Formyloxy)methyl]furfural; 5-Hydroxymethylfurfural; Fructose; Deep Eutectic Solvents; Purification
A hydrogel-coated membrane for highly efficient separation of microalgal bio-lipid by Jihye Shin; Hogi Kim; Heeyeon Moon; Moo Jin Kwak; Seula Oh; Youngmin Yoo; Eunjung Lee; Yong Keun Chang; Sung Gap Im (1319-1327).
A cross-linked hydrogel-coated membrane was fabricated to achieve simple but highly efficient separation of bio-lipids directly from an aqueous microalgal culture medium. The membrane is composed of a stainless steel membrane coated conformally with a cross-linked hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), synthesized by a photo-initiated chemical vapor deposition (piCVD) process. The pHEMA-coated membrane has hydrophilicity and underwater-oleophobicity for efficient separation of a bio-lipid-in-hexane/water mixture by gravity. The conformal pHEMA film-coated membrane enables extremely high oil rejection performance with intrusion pressure of 6.1 kPa and water permeation flux of 6.5×103 L m-2 h-1, with excellent separation efficiency greater than 98.0%.
Keywords: Membrane; Hydrophilic; Underwater-oleophobic; Cross-linked Hydrogel; Bio-lipid Separation; Photo-initiated Chemical Vapor Deposition (piCVD)
Liquid-liquid equilibria for water+2,3-butanediol+1-pentanol ternary system at different temperatures of 298.2, 308.2, and 318.2 K by A. Young Jeong; Jeong Ah Cho; Yugyeom Kim; Hang-Kyu Cho; Kyu Yong Choi; Jong Sung Lim (1328-1334).
Liquid-liquid equilibrium (LLE) data was measured for the water+2,3-butanediol+1-pentanol ternary system at 298.2, 308.2, and 318.2 K under atmospheric pressure. Binodal solubility curves and complete ternary phase diagrams were experimentally obtained in mass fraction at these three different temperatures. The consistency of the tieline results was verified by using Othmer-Tobias and Hand plots. Distribution coefficients and separation factors of 2,3- butanediol were evaluated for each tie-line, and the effect of temperature was also investigated. It was found that the distribution coefficients and separation factors of 2,3-butanediol increased with temperature. The experimental LLE data were correlated by the UNIQUAC and NRTL models, and the binary interaction parameters calculated from these models have been reported. Both models successfully predict the experimental tie-line data within average root-mean-square deviations (RMSD) being less than 1.38% and 1.49% from the UNIQUAC and NRTL models, respectively.
Keywords: 2,3-Buthanediol; 1-Pentanol; Liquid-liquid Equilibrium; NRTL; UNIQUAC
Equilibrium solubility of CO2 in aqueous binary mixture of 2-(diethylamine)ethanol and 1, 6-hexamethyldiamine by Shailesh Kumar; Monoj Kumar Mondal (1335-1340).
CO2 solubility data are important for the efficient design and operation of the acid gas CO2 capture process using aqueous amine mixture. 2-(Diethylamino)ethanol (DEEA) solvent can be manufactured from renewable sources like agricultural products/residue, and 1,6-hexamethyldiamine (HMDA) solvents have higher absorption capacity as well as reaction rate with CO2 than conventional amine-based solvents. The equilibrium solubility of CO2 into aqueous binary mixture of DEEA and HMDA was investigated in the temperature range of 303.13-333.13 K and inlet CO2 partial pressure in the range of 10.133-20.265 kPa. Total concentration of aqueous amine mixtures in the range of 1.0-3.0 kmol/m3 and mole fraction of HMDA in total amine mixture in the range of 0.05-0.20 were taken in this work. CO2 absorption experiment was performed using semi-batch operated laboratory scale bubble column to measure equilibrium solubility of CO2 in amine mixture, and CO2 absorbed amount in saturated carbonated amine mixture was analyzed by precipitation-titration method using BaCl2. Maximum equilibrium CO2 solubility in aqueous amine mixture was observed at 0.2 of HMDA mole fraction in total amine mixture with 1.0 kmol/m3 total amine concentration. New solubility data of CO2 in DEEA+HMDA aqueous mixtures in the current study was compared with solubility data available in previous studies conducted by various researchers. The study shows that the new absorbent as a mixture of DEEA+HMDA is feasible for CO2 removal from coal-fired power plant stack gas streams.
Keywords: Equilibrium Solubility; Carbon Dioxide; 2-(Diethylamine)ethanol; 1,6-Hexamethyldiamine
Gd3+ doped Fe3O4 nanoparticles with proper magnetic and supercapacitive characteristics: A novel synthesis platform and characterization by Mustafa Aghazadeh; Isa Karimzadeh; Mohammad Ghannadi Maragheh; Mohammad Reza Ganjali (1341-1347).
A novel electrochemical procedure was developed for the facile preparation of Gd-doped iron oxide nanoparticles (GdIO-NPs). A simple galvanostatic deposition (i=10 mA cm-2) was done in an additive-free aqueous solution containing FeCl2·4H2O, Fe(NO3)3·9H2O and GdCl3·6H2O. The XRD, FE-SEM, EDS and TEM characterizations showed that the product is composed of 15% GdIO-NPs with 10 nm in size. VSM analysis proved that the GdIO-NPs are superparamagnetic. The cyclic voltammetry and charge-discharge tests showed that the prepared GdIO-NPs are capable to deliver specific capacity as high as 190.1 F g-1 at 0.5A g-1 and capacity retention of 95.1% after 2000 cycling. Based on the results, it was concluded that the developed electrochemical strategy acts as an efficient procedure for the preparation of lanthanide doped MNPs with proper magnetic and supercapacitive characters.
Keywords: Iron Oxide; Gd Ion Doping; Nanoparticles; Electrodeposition; Magnetic Materials; Supercapacitors
Damage to amorphous indium-gallium-zinc-oxide thin film transistors under Cl2 and BCl3 plasma by Jong Hoon Choi; Sung Jin Kim; Hyung Tae Kim; Sung Min Cho (1348-1353).
Plasma damage of indium-gallium-zinc-oxide (IGZO) thin film transistor (TFT) was investigated. The IGZO TFT was fabricated and the performance was measured before and after BCl3 and/or Cl2 plasma treatment to evaluate the IGZO damage. The BCl3 and/or Cl2 plasma deteriorated the IGZO TFT performance significantly even after a short exposure time in the plasma. We propose a new wet etching process to remove a source/drain metal without damaging the underlying IGZO layer. The wet etching process can be utilized for the fabrication of IGZO TFT array using a roll-to-roll process via a self-aligned imprint lithography technique.
Keywords: Indium-gallium-zinc-oxide (IGZO); Thin Film Transistor (TFT); Plasma Damage; Plasma Etching
Organosilicon resin-based carbon/ceramic polygranular composites with improved oxidation resistance by Krystian Sokolowski; Aneta Fraczek-Szczypta; Janusz Tomala; Stanislaw Blazewicz (1354-1364).
We examined the thermo-mechanical properties of carbon materials modified with silicon oxycarbide (Si-O-C) and silicon carbide (Si-C). These compounds were obtained by the impregnation of carbon components with a silicon-containing polymer resin. Graphite and anthracite powders were used as carbon components, and poly[methyl(phenyl) siloxane] resin (P) was used as the ceramic precursor. Carbon/polymer compositions (C/P) were subjected to two-stage annealing, first to 1,000 °C and next to 2,000 °C in an inert atmosphere, leading to the formation of C/Si-O-C and C/Si-C composite samples, respectively. The materials were then examined under conditions of isothermal oxidation to determine their oxidation resistance and the mechanical properties before and after oxidation tests. The structure of the samples before and after oxidation was studied. C/Si-C composites, despite their high porosity, proved to have enhanced resistance to oxidation at 600 °C, although they had lower mechanical properties in comparison to C/Si-O-C samples.
Keywords: Polysiloxane Resin; Carbon Materials; Silicon Oxycarbide; Silicon Carbide; Oxidation Resistance
Synthesis and characterization of decyl phosphonic acid, applications in emulsion polymerization and anti-corrosion coating by The-Anh Phan; François-Xavier Perrin; Lam Nguyen-Dinh (1365-1372).
Alkyl phosphonic acids are amphiphilic structures consisting of non-polar organic hydrophobic groups and anionic inorganic hydrophilic groups, which makes them be able to behave as surfactants as well as smart corrosion inhibitors. A simple and high yield (up to 87%) pathway for synthesizing decyl phosphonic acid (DPA) is described. 1H and 13C-NMR) as well as FTIR spectroscopy were used to characterize chemical structures and purity of the obtained product. Thermal properties and crystal structure of DPA were investigated using differential scanning calorimetry analysis (DSC) and thermogravimetric analysis (TGA). The stability of DPA in Oil-in-Water (O/W) and Water-in-Oil (W/O) emulsions was improved in the presence of ammonium persulfate (APS), which allowed us to measure their specific characteristics such as particle size and zeta potential (ξ) of micelles. Both emulsions were used for synthesizing polyaniline (PANI) by emulsion polymerization. Wettability of DPA on the mild steel surface was examined using contact angle measurements. Moreover, corrosion-inhibition properties studied by using electrochemical impedance spectroscopy (EIS) technique and salt spray test results revealed that DPA can be an efficient ingredient for anti-corrosion coating.
Keywords: Surfactant; Oil-in-water Emulsion; Water-in-oil Emulsion; Polyaniline
Two dimensional Zn-stilbenedicarboxylic acid (SDC) metal-organic frameworks for cyclic carbonate synthesis from CO2 and epoxides by Gak-Gyu Choi; Jintu Francis Kurisingal; Yongchul G. Chung; Dae-Won Park (1373-1379).
A two-dimensional Zn-based metal-organic framework has been synthesized by using Zn(II) ions and H2SDC (4,4′-stilbenedicarboxylic acid) under solvothermal conditions. The framework having a trinuclear Zn3-(RCO2)6 SBUs connected by the 4,4′-stilbenedicarboxylic acid to form a hexagonal network, shows a two-dimensional structure and displays high thermal stability up to approximately 330 °C. The role of Zn2+ (from Zn-SDC) for epoxide activation and Br-ion (from TBABr) for ring opening of epoxide was studied for the cycloaddition reaction of CO2 and propylene oxide (PO) under ambient conditions. Zn-SDC was found catalytically efficient towards CO2-epoxide coupling under ambient reaction conditions with high selectivity towards the desired cyclic carbonates under solvent-free conditions. The effects of various reaction parameters such as catalyst loading, temperature, CO2 pressure, and time were evaluated. Zn-SDC was easily separable and reusable at least five times without any considerable loss in the initial activity. A plausible reaction mechanism for the cycloaddition reaction was also proposed based on literature and experimental inferences.
Keywords: Metal Organic Frameworks; Zn-SDC; CO2 ; Epoxide; Cyclic Carbonate
Effect of inlet particle arrangement on separating property of a cyclone separator by An-Lin Liu; Yan-Hong Zhang; Liang Ma; Yi-Mou Wang; Meng-Ya He (1380-1387).
Different arrangements of particles on the inlet section exert different effects on the separation property of a cyclone separator. Sorting classifier with different heights was connected in series with a conventional cyclone, positive rotation cyclone, and reverse rotation cyclone respectively, to investigate the effect of particle arrangement on the separation property and inner flow field. Results indicate that the implementation of a sorting classifier increases the pressure drop and energy consumption of a cyclone separator. The taller the sorting classifier, the larger the flow is. The energy consumption in positive rotation cyclone is closer to that in reverse rotation cyclone. Meanwhile, the tangential velocity in inner flow field is higher and the separating property is enhanced. The reverse rotation cyclone relieves the fishhook effect, whereas the positive rotation cyclone eliminates such effect. The reverse and positive rotation cyclones demonstrate an improved separating property for particles smaller and greater than 1 μm, respectively. Moreover, the reverse rotation cyclone demonstrates superior overall separation, but the positive rotation cyclone demonstrates a greater classification effect than the reverse rotation cyclone.
Keywords: Cyclone Separator; Particle Arrangement; Particle Image Velocimetry (PIV); Separating Property